Process crash via misaligned variable-length string pointer
Published Aug 5, 2026 · Updated Aug 5, 2026
Untrusted pointer dereference in HDF5 h5dump 2.3.0 and earlier allows attackers to crash the tool via a crafted HDF5 file. In native binary output mode, render_bin_output miscalculates the stride for multi-element variable-length strings, reads later elements at misaligned offsets, and dereferences those bytes as pointers. The attacker must cause an operator to process the file with native binary output; successful exploitation terminates only that h5dump process with SIGSEGV.
Summary
What happened
Untrusted pointer dereference in HDF5 h5dump 2.3.0 and earlier allows attackers to crash the tool via a crafted HDF5 file. In native binary output mode, render_bin_output miscalculates the stride for multi-element variable-length strings, reads later elements at misaligned offsets, and dereferences those bytes as pointers. The attacker must cause an operator to process the file with native binary output; successful exploitation terminates only that h5dump process with SIGSEGV.
The record
- CVE
- CVE-2026-19023
- Published
- Aug 5, 2026
- Updated
- Aug 5, 2026
- Vendor
- The HDF Group
- Product
- HDF5
- Classifications
- CWE-822, CAPEC-129, T1204.002
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Aug 5, 2026CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=<= 2.1.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Native binary-output crash reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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